I'm trying to package a binary version of GHC (attached), which fails
with the following error:

/nix/store/snrdydzbrw9aqnz569k73dmk67wn1akv-my-coreutils-8.20/bin/install -c -m 755 -d "/nix/store/gy7g3k7bwpaf7pvm70d0rn8xh8b7rq6h-ghc-bin-7.0.1/lib/ghc-7.0.1/package.conf.d"
"/nix/store/gy7g3k7bwpaf7pvm70d0rn8xh8b7rq6h-ghc-bin-7.0.1/lib/ghc-7.0.1/ghc-pkg" --force --global-conf "/nix/store/gy7g3k7bwpaf7pvm70d0rn8xh8b7rq6h-ghc-bin-7.0.1/lib/ghc-7.0.1/package.conf.d" update libffi/package.conf.install
/nix/store/zkg7nnj03yp6pg9gx8wq3lpalr4ffw71-bash-4.2/bin/sh: /nix/store/gy7g3k7bwpaf7pvm70d0rn8xh8b7rq6h-ghc-bin-7.0.1/lib/ghc-7.0.1/ghc-pkg: No such file or directory
make[1]: *** [install_packages] Error 127
make: *** [install] Error 2
phase `install' failed after 2 seconds
note: keeping build directory `/tmp/nix-build-ghc-bin-7.0.1.drv-16'
builder for `/nix/store/8ifycdgaisy3n6xsxkm05cklcmra40yw-ghc-bin-7.0.1.drv' failed with exit code 1
@ build-failed /nix/store/8ifycdgaisy3n6xsxkm05cklcmra40yw-ghc-bin-7.0.1.drv - 1 builder for `/nix/store/8ifycdgaisy3n6xsxkm05cklcmra40yw-ghc-bin-7.0.1.drv' failed with exit code 1
guix build: error: build failed: build of `/nix/store/8ifycdgaisy3n6xsxkm05cklcmra40yw-ghc-bin-7.0.1.drv' failed

I'm not sure what causes the problem.  I don't see anything strange in
makefiles.  Should I patch executables?  Here is a relevant snippet from
'6.12.1-binary.nix':

    (if stdenv.isLinux then ''
      find . -type f -perm +100 \
          -exec patchelf --interpreter "$(cat $NIX_GCC/nix-support/dynamic-linker)" \
          --set-rpath "${ncurses}/lib:${gmp}/lib" {} \;
      sed -i "s|/usr/bin/perl|perl\x00        |" ghc-${version}/ghc/stage2/build/tmp/ghc-stage2
      sed -i "s|/usr/bin/gcc|gcc\x00        |" ghc-${version}/ghc/stage2/build/tmp/ghc-stage2
      for prog in ld ar gcc strip ranlib; do
        find . -name "setup-config" -exec sed -i "s@/usr/bin/$prog@$(type -p $prog)@g" {} \;
      done
     '' else "");

What do you think?

P.S. I'm using a previous version of 'coreutils' (i.e., 'my-coreutils'),
which should be removed from the recipe.